/*
 * Copyright 2010-2020 Alfresco Software, Ltd.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.activiti.validation.validator.impl;

import java.util.ArrayList;
import java.util.List;
import org.activiti.bpmn.model.BpmnModel;
import org.activiti.bpmn.model.ExclusiveGateway;
import org.activiti.bpmn.model.Process;
import org.activiti.bpmn.model.SequenceFlow;
import org.activiti.validation.ValidationError;
import org.activiti.validation.validator.Problems;
import org.activiti.validation.validator.ProcessLevelValidator;
import org.apache.commons.lang3.StringUtils;

/**

 */
public class ExclusiveGatewayValidator extends ProcessLevelValidator {

    @Override
    protected void executeValidation(BpmnModel bpmnModel, Process process, List<ValidationError> errors) {
        List<ExclusiveGateway> gateways = process.findFlowElementsOfType(ExclusiveGateway.class);
        for (ExclusiveGateway gateway : gateways) {
            validateExclusiveGateway(process, gateway, errors);
        }
    }

    public void validateExclusiveGateway(
        Process process,
        ExclusiveGateway exclusiveGateway,
        List<ValidationError> errors
    ) {
        if (exclusiveGateway.getOutgoingFlows().isEmpty()) {
            addError(errors, Problems.EXCLUSIVE_GATEWAY_NO_OUTGOING_SEQ_FLOW, process, exclusiveGateway);
        } else if (exclusiveGateway.getOutgoingFlows().size() == 1) {
            SequenceFlow sequenceFlow = exclusiveGateway.getOutgoingFlows().get(0);
            if (StringUtils.isNotEmpty(sequenceFlow.getConditionExpression())) {
                addError(
                    errors,
                    Problems.EXCLUSIVE_GATEWAY_CONDITION_NOT_ALLOWED_ON_SINGLE_SEQ_FLOW,
                    process,
                    exclusiveGateway
                );
            }
        } else {
            String defaultSequenceFlow = exclusiveGateway.getDefaultFlow();

            List<SequenceFlow> flowsWithoutCondition = new ArrayList<SequenceFlow>();
            for (SequenceFlow flow : exclusiveGateway.getOutgoingFlows()) {
                String condition = flow.getConditionExpression();
                boolean isDefaultFlow = flow.getId() != null && flow.getId().equals(defaultSequenceFlow);
                boolean hasConditon = StringUtils.isNotEmpty(condition);

                if (!hasConditon && !isDefaultFlow) {
                    flowsWithoutCondition.add(flow);
                }
                if (hasConditon && isDefaultFlow) {
                    addError(
                        errors,
                        Problems.EXCLUSIVE_GATEWAY_CONDITION_ON_DEFAULT_SEQ_FLOW,
                        process,
                        exclusiveGateway
                    );
                }
            }

            if (!flowsWithoutCondition.isEmpty()) {
                addWarning(errors, Problems.EXCLUSIVE_GATEWAY_SEQ_FLOW_WITHOUT_CONDITIONS, process, exclusiveGateway);
            }
        }
    }
}
